Immunoglobulin-like transcripts (ILTs) are also known as Leukocyte Immunoglobulin-like receptors (LIRs), monocyte/macrophage immunoglobulin-like receptors (MIRs) and CD85. This family of immunoreceptors form part of the immunoglobulin superfamily. The identification of ILT molecules was first published in March 1997 in a study (Samaridis et al., (1997) Eur J Immunol 27 660-665) which detailed the sequence of LIR-1 (ILT-2), noted their similarity to bovine FCγ2R, human killer cell inhibitory receptors (KIRs), human FcαR, and mouse gp49. This study also noted that LIR-1, unlike KIRs, is predominately expressed on monocytic and B lymphoid cells.
Soluble polypeptides with the pMHC binding characteristics of ILT molecules and multivalent complexes thereof provide a means of blocking the CD8 binding site on pMHC molecules, for example for the purpose of inhibiting CD8+ T cell-mediated automimmune disease. However, for that purpose it would be desirable if these polypeptides had a higher affinity and/or a slower off-rate for the target pMHC molecules than native ILT molecules.